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Aspirin is one of the medications used to reduce pain, inflammation, and temperature. It has been used for several decades and remains an option even after the introduction of other non-steroidal anti-inflammatory drugs (NSAIDs). Although today, many medical professionals only prescribe or recommend aspirin for people with certain heart problems, as aspirin has been shown to reduce the risk of blood clotting.
Since aspirin is present in many home medical kits, you may notice that after a while in storage, the aspirin will start to smell like vinegar. The chemical explanation for this can be simplified by understanding the chemical nature of aspirin and vinegar.
The chemical nature of aspirin
Aspirin is known chemically as acetylsalicylic acid. After some time, or when stored under non-ideal conditions, it will easily deteriorate into acetic acid and salicylic acid, even without the presence of other chemicals.
The chemical nature of vinegar
Vinegar came from the fermented juices of fruits that contain sugars. The initial fermentation of the freshly extracted juices will result in the creation of the wine. If fermentation is allowed to continue, the alcohol in the wine will convert to acetic acid. Acetic acid gives vinegar and related products that distinctive sour taste and odor.
Why does aspirin smell like vinegar?
When aspirin begins to break down, its molecules will separate into salicylic acid and acetic acid. Having acetic acid as a breakdown product of aspirin gives it an odor similar to vinegar (which has dilute amounts of acetic acid as a component).
How to store aspirin
To slow down the breakdown process of aspirin, it must be stored in proper conditions.
1. Store container in a cool, dry place.
Exposure to moisture will facilitate the hydrolysis of the aspirin molecules into their breakdown products.
2. Keep the container tightly closed.
Exposure to air provides the oxygen required for the oxidation of aspirin to acetic acid and salicylic acid.
3. Keep aspirin (and other medicines) away from areas with a lot of sunlight.
Bright lighting conditions can also accelerate the deterioration of many drugs. They are best stored in amber colored bottles.
Several years after aspirin was manufactured, it is expected to slowly deteriorate and lose effectiveness. To slow down the deterioration process, follow proper storage procedures. And if you have aspirin tablets that smell strongly of vinegar, throw them away. You just have to go to the nearest pharmacy. Aspirin rarely runs out.